Fire　is　a　typical　thermal　runaway　process　of　uncontrolled　energy　release.　The　possible　ignition　of　adjacent　leaked　fuel　might　induce　multiple　fires　burning　simultaneously.　A　series　of　numerical　simulations　have　been　conducted　to　study　the　flame　merging　behavior　and　air　entrainment　restriction　effect　from　square　propane　fire　arrays.　The　simulation　results　were　first　systematically　compared　to　experimental　data,　showing　that　the　flame　characteristics　including　the　flame　height,　flame　centerline　temperature,　and　velocity　distributions　can　be　successfully　reproduced　numerically.　Then,　the　flame　merging　phenomenon　was　studied　by　varying　fire　spacing,　the　number　of　fires,　and　the　heat　release　rate　of　an　individual　fire　in　the　array.　Results　show　that　the　critical　flame　merging　spacing　of　the　fire　array　equals　to　0.4　times　the　flame　height　of　a　single　fire,　which　is　independent　of　the　fire　array　size.　More　importantly,　a　parameter　denoting　the　extent　of　air　entrainment　restriction　α　was　introduced,　which　enables　a　characterization　of　the　air　entrainment　restriction　effect　of　a　fire　array.　A　maximum　air　entrainment　restriction　model　was　established,　which　is　shown　only　related　to　the　number　of　fires　in　the　array.　©　2020　Elsevier　Ltd